Copolymers of butadiene and monocyclic terpene alcohol esters of acrylic acids



Patented Feb. 7, 1959 COPOLYMEES F 'BUTADIENE AND MONO- CYCLIC TERPENE ALCOHOL ESTERS OF ACRYLIC ACIDS Albert M. Clifford, Stow,

foot Corporation, Akron,

of Delaware No Drawing. Original Divided and this applica- 1944, Serial No. 529,411

Serial No. 339,391. tion April 3,

Ohio, assignor to Wing- Oliio, a corporation application June '7, 1940,

3 Claims. (Cl. 260-835) This invention relates to polymers of certain esters of acrylic acids with other polymerizable substances which yield materials of useful character. This application is a division of my application Serial No. 339,391, filed June 7,1940, now Patent Number 2,363,044.

Various esters of acrylic acids, such as esters of methacrylic acid, have been prepared and have been polymerized with the object of securing materials of high molecular weight, intended for use as plastics, varnishes, and the like. It has now been found that the esters prepared by the interaction of terpene derivatives and acrylic acids are particularly useful monomers for the preparation of industrial materials. The invention includes the copolymers or interpolymers oi the terpene esters of the various acrylic acids as one of the monomeric materials and a vinyl com pound, such as butadiene, as the other monomeric compound. The copolymers formed from the monocyclic terpene esters of acrylic acid and its alpha alkyl homologues have been found to be particularly useful, and these copolymers, therefore, constitute the preferred form of the invention.

The terpene esters of acrylic acids may be prepared by reacting the acid with the terpene in the form of the alcohol or by reacting the sodium salt of the acid with a terpene halide, such as the terpene chloride. Still another method of forming the esters is by reacting a lower alkyl ester of the acrylic acid with the terpene alcohol in an ester interchange, a catalyst being used to promote the interchange.

Among the terpene alcohols whose esters characterize the copolymers of the invention may be mentioned alpha terpineol, beta terpineol, menthol, carvomenthol, carveol, dihydrocarveol, fenchyl alcohol, isofenchyl alcohol, pulegol, terpin, the alkyl derivatives of the foregoing and similar bodies. Of course, the chlorides corre sponding to the foregoing materials may be reacted with the sodium salt of the acrylic acid to obtain the same result. Other terpene esters are included, those mentioned serving merely to illustrate the class of terpenes, the alcohols or halides of the entire class being available or readily prepared. The monocyclic terpene esters are new compounds and are illustrated by the terpineol, menthol, carvomenthol, carveol, dihydrocarveol, methyl carveol, pulegol and terpin acrylates, methacrylates, ethacrylates and similar monocyclic terpene esters of the various acrylic acids.

The acrylic acid which reacts with the terpene compound to form the ester may be acrylic acid itself or a substituted acrylic acid, such as methacrylic acid, alpha chloroacrylic acid, ethacrylic alkyl radicals acid, propacrylic acid, the alpha halogen alkyl acrylic acids, such as alpha chlor methyl acrylic acid, alpha chlor ethyl acrylic acid, and the like. However, the preferred class of esters for the formation of the polymerization products of the invention consists of those acids in which the alpha carbon atom carries hydrogen or an alkyl substituent; i. e., those acids having the formula where R is selected from the group consisting of and hydrogen. Actually, in the reaction the acid itself will not ordinarily be employed but, instead, either the acid halide, such as the acid chloride, or a lower alkyl ester of the acid, an ester exchange taking place in the latter case.

The conditions under which the reaction is conducted are mild; for example, the terpene al- 001101 may be reacted with the lower alkyl ester of the acrylic acid on the water bath or on an oil bath at temperatures ranging from -150 C. The reaction is conducted under a reflux condenser operated at such a temperature that the lower alcohol formed ,n the exchange may be eliminated from the reaction mixture. Ordinarily, the reaction is completed in from four to eight hours, but a longer time may be employed if necessary. Also, a catalyst may be present to promote reaction, sulfuric acid or sodium methylate being effective in bringing about the ester exchange. A'polymerization inhibitor, such as hydroquinone or phe'nyl beta naphthylamine, should also be employed to avoid polymerization of the ester during the reaction. The terpene alcohol and the ester of an acrylic acid may be reacted in various proportions, the mono molec ular combination usually being desired, but generally the acrylate, such as the lower alkyl ester, will be present in amount from 1 to l or even 8 mols to each mol of the terpene alcohol. Where the halide of the acid is employed, the desired ester may be obtained in the conventional manner by reaction with the terpene alcohol. The same conditions as to temperature and propor tions apply as in the case of the ester exchange.

The terpene esters of the acrylic acids are usually light-colored liquids which rapidly polymerize on standing if not protected by an inhibitor. Mass polymerization takes place rapidly in the presence of catalysts, such as benzoyl per oxide, sodium perborate, and the like, standing for a few hours or a few days at room ternperature resulting in clear, glass-like, tough polymers. These polymers form viscous solutions in solvents, such as ethylene dichloride, chloroform, and other chlorinated solvents, the solutions, on

evaporation, leaving clear films of excellent adhesive properties.

The esters also undergo copolymerization with various other monomeric vinyl compounds, such as butadiene, styrene and its homologues, vinylidene chloride, vinyl chloride, acrylonitrile, methacrylonitrile, ethacrylonitrile, 2-cyano butadiene, 2-chloro butadiene, vinyl acetate, etc. The copolymer, in such cases, will contain preferably at least 25 per cent of the terpene ester and of the vinyl compound although lesser amounts will also give useful materials.

For example, the new esters may be interpolymerized with butadiene-1,3 to give soft, flexible, and decidedly rubber-like copolymers. This copolymerization can be conducted conveniently in 10 cc. solution of Aquarex D cc. of a buffer solution 0.133 g. NaBOaAHzO 0.48 g. carbon tetrachloride 9.4 g. butadiene 1:3

6.4 g. the acrylate, as specified prepared. First, an emulsion was prepared containing the following ingredients:

20 cc. 3% solution Na oleate 0.133 g. NaBOaAHzO 0.48 g. C014 To this was then added the specified quantities of butadiene and styrene or acrylic nitrile, together with terpinyl methacrylate.

Percent styrene Yield Terpinyl Methacry- 9? late N1 rile diene The copolymers thus prepared had properties varying from tacky to tough and included rubber-like compositions.

While there have been described above certain preferred embodiments of the invention, it will be understood that the same is not limited thereto but all features of patentable novelty residing in such invention.

What I claim is:

1. Copolymers comprising terpinyl methacrylate interpolymerized with butadiene-1,3 in which the ester and butadiene are each present to the extent of at least 25 per cent of the copolymer.

2. A copolymer resulting from the polymerization of a mixture comprising monomeric butadiene and a terpene ester of a monocyclic terpene alcohol and an acrylic acid having the general formula CHzICRCOzH in which R is selected from the group consisting of alkyl radicals, chlorine and hydrogen, in which the butadiene and ester are each present to the extent of at least 25%.

3. A copolymer resulting from the polymerization of a mixture comprising monomeric butadiene and a terpene ester of a ring-unsaturated ALBERT M. CLIFFORD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Rupe: Annalen der Chem. vol. 369 (1909-10), page 336, copy in Scientific Library. 

1. COPOLYMERS COMPRISING TERPINYL METHACRYLATE INTERPOLYMERIZED WITH BUTADIENE-1,3 IN WHICH THE ESTER AND BUTADIENE ARE EACH PRESENT TO THE EXTENT OF THE LEAST 25 PER CENT OF THE COPOLYMER. 